Question

Formaldehyde when reacted with methyl magnesium bromide followed by hydrolysis?
(A) $ {{C}_{2}}{{H}_{5}}OH $
(B) $ C{{H}_{3}}COOH $
(C) $ HCHCO $
(D) $ C{{H}_{3}}CHO $

Answer 1

Hint :We know that to answer the question firstly we should find the product from the reaction between formaldehyde and methyl magnesium bromide and then we will do the hydrolysis of the product obtained by the reaction of formaldehyde and methyl magnesium bromide.

Complete Step By Step Answer:
Here to answer the hydrolysis product, of all we should find the product from the reaction between formaldehyde and ethyl magnesium bromide and then we will do the hydrolysis of that product.
Firstly let us look at the reaction we are going to perform here
 $ C{{H}_{3}}MgBr\text{ + HCHO }\to \text{ A }\xrightarrow{{{H}_{3}}{{O}^{+}}}\text{ B} $
So, the above reaction explains the question and how we are going to react to the reactants. Firstly we will find the product A that we gain from the reaction of formaldehyde and methyl magnesium bromide. So when we look at this reaction we come to know that this reaction is in Grignard reagent reactions. So firstly we will know how the Grignard reagent will react with this.
So here the methyl magnesium bromide will dissociate into methyl with negative charge and magnesium bromide with positive charge, so magnesium bromide will attack on the oxygen part and negative part will get attached to the carbon atom in formaldehyde. The reaction will takes place as follows
 $ C{{H}_{3}}MgBr\text{ + HCHO }\to \text{ C}{{\text{H}}_{2}}\text{(}{{\text{O}}^{-}}\text{MgB}{{\text{r}}^{+}}\text{)C}{{\text{H}}_{3}}\text{ }\xrightarrow{{{H}_{3}}{{O}^{+}}}\text{ B} $
Now the hydrolysis takes place and the $ {{O}^{-}}MgB{{r}^{+}} $ Term will be terminated by $ OH $ , so the final product will be as follows
 $ C{{H}_{3}}MgBr\text{ + HCHO }\to \text{ C}{{\text{H}}_{2}}\text{(}{{\text{O}}^{-}}\text{MgB}{{\text{r}}^{+}}\text{)C}{{\text{H}}_{3}}\text{ }\xrightarrow{{{H}_{3}}{{O}^{+}}}\text{ C}{{\text{H}}_{3}}C{{H}_{2}}OH $
Therefore, the correct answer is option A i.e. $ {{C}_{2}}{{H}_{5}}OH $ and its IUPAC name is Ethanol.

Note :
Remember that the reason for using magnesium in Grignard reagent. The reaction to the formation of Grignard reagents requires the use of magnesium ribbon. All magnesium is covered with a passivation film of magnesium oxide, which prevents reactions to organic halide. The application of Grignard preformed reagent is also used as an initiator. We should note that formaldehyde is a colourless, strong-smelling gas used in making building materials and many household products. It is best known for its preservative and anti-bacterial properties.